The same sometimes when loading Nebula (Server for me-Core 3) on Logic Pro and AE Wave Editor.
The only thing to do is stop playback, add plugin, wait.
(Ignore strange noises, sometimes happens to me too...)
In case you smell the hang on Logic use quickly forced exit from 32 bit bridge and reload it (keep it in the dock)
On Wave Editor remove plugin and retry
I think it's for the loading time (Nebula with some presets is quite heavy) some daws have still problems with it.
I don't think it's Nebula fault, it's that some daws-hosts are not prepared to it, or maybe it's the entrance of new dev bug
Report problems is the right thing to do anyway, keep doing it